Internal combustion engine



o bl Nu e v n 3 0. Z. FRAZIER INTERNAL COMBUSTION ENGINE Flled Sept 81937 2 SheetsSheet 1 Orv Aug. 15, 1939 Gttorneg Aug. 15, 1939 o z.FRAZIER 'L'NTERNAL COMBUSTION ENGINE Filed Sept. 8, 1937 2 Sheets-Sheet2 Oil 17h Z. Fin z 01- Patented Aug. 15, 1939 UNITED STATES PATENTOFFICE INTERNAL COMBUSTION ENGINE Application September 8, 1937, SerialNo. 162,913

3 Claims.

This invention relates to internal combustion engines and particularlytwo-cycle engines.

An object of the invention is to provide a light compact engine,designed to operate at high speeds and especially adapted to be built insmall sizes, suited for driving model aeroplanes or boats.

Another object is to so construct a single cylinder internal combustionengine that its crank shaft may be elongated to comprise a plurality ofcrank-throws, and a number of said engines may be rigidly secured inside-by-side relation to jointly drive the crank-shaft, thus forming amulti-cylinder engine.

Another object is to so mount a fuel tank on such an engine that thebottom of said tank is formed by an extension of a plate forming thebottom of the crank case.

These and various other objects are attained by the constructionhereinafter described and illustrated in the accompanying drawings,wherein:

Fig. 1 is a view of the improved engine in axial vertical section.

Fig. 2 is a relatively transverse sectional view of the engine.

Fig. 3 is a perspective view of the crank shaft, showing its partsdisassembled.

Fig. 4 is a sectional view taken on the line 44 of Fig. 1, and showingthe spark timer and its controlling cam.

Fig. 5 is a. fragmentary cross-sectional view, taken on the line 55 ofFig. 2, and showing how a fuel feed duct is connected to the crank case.

Fig. 6 is a fragmentary cross-sectional view, taken on the line 68 ofFig. 2, and showing the connection of said fuel feed duct to the enginecylinder.

Fig. 7 is a side elevational view disclosing how a number of the enginesshown in Figs. 1 and 2 may be combined to form a multl-cyllnder engine.

Fig. 8 is a front view of a block used in said multi-cylinder engine toproperly space the engine units. K Fig. 9 is a sectional view of thesame, taken on the line 9-9 of Fig. 8.

In these views, the reference character I designates a cylinder,integrally headed at its upper end and exteriorly formed on its upperportion 'withya suitable number of spaced, annular, heatdissipating fins2. The usual spark plug 3 is mounted in the cylinder head, so as to forma spark gap in the combustion chamber. The cylinder I surmounts acrankcase 4, serving additionally as a compression chamber for anexplosive charge, as is usual in two cycle engines, and a connecting rod5a extends downwardly from a piston 5, reciprocatory in said cylinder,to engage a crank pin 6 in the crank case 4. Said crank pin is connectedby a pair of similar throw arms I to aligned sections 8 and 9 of a crankshaft, said sections being journaled in bearings l0 exteriorly extendingfrom a pair of heads H which form end closures for the chamber 4. Saidheads are interconnected and secured tightly in place by a set of boltsl2, extending exteriorly of the crank case. Preferably the throw armsare integrally counter-weighted, as indicated at la.

At one side of the crank case, there is provided a fuel tank I3, and asshown, this tank is formed by a cylindrical wall clamped between anunderlying plate l4 and a cover l5, both carried by the engine. Thus theplate I 4 is an extension of. a bottom closure for the crank case 4,being bolted to the latter, as indicated at IS. The cover I5 isintegrally connected to the crank case and cylinder by a vertical web H,which further in tegrally carries a duct I8 receiving fuel from a tube19 disposed axially of the tank l3 and having an inlet end adjacent tothe bottom of said tank. The duct is extends from its connection withthe tube l9 toward the cylinder, preferably at an upward inclination,the outer portion of said duct beingtapped to adjustably mount a needlevalve 20, regulating the fuel flow. The inner or discharging end of theduct opens into a port 2| in the cylinder wall through which air may bedrawn, in the illustrated raised position of the piston. Above the port21 isthe usual exhaust port 22 and opposite to the latter a by-pass 23,rising from the crank case, is adapted to communicate with thecombustion chamber, in the lowered position of the piston.

The crank shaft, as best appears in Fig. 3, is an assemblage of partsadapted to be clamped together in working relation. Thus the throw armsI have square holes 24 for receiving the squared ends of the crank pin 6and square holes 25 for receiving squared ends of the two shaftsections. To adapt the throw arms to be firmly clamped to the crank pinand shaft sections, said arms are centrally formed with slots 26extending from their counter-weighted ends and intersecting the holes 24and 25. A clamping screw 27 mounted in each counterweight extends acrossthe corresponding slot 26 to draw the bifurcations of the arm together,and a second clamping screw 28 connects the bifurcations at a pointbetween the holes 24 and 25 to supplement the screw 21. Prior to thusassembling the crank shaft, the connecting rod 5a is of course engagedwith the crank pin.

The free end portion of one of the bearings I0 is slightly reduced indiameter to mount a sparktiming unit. This unit comprises a bracket 28,apertured to engage said free end portion and upstanding from the latterand surmounted by a suitable handle. (See Fig. 4.) Pivoted on saidbracket is a rocker arm 30, free at one end and extending across thecrank shaft, and carrying a fiber lug 3i riding on a cam 32, fixed onthe crank-shaft. The free end of the arm 30 carries one of a pair ofcoacting contact points 33, the other of which is fixed on said bracket.A spring 34 acts on the arm 30, urging the contact points toward anengagement which is permitted by the cam at one point in its periphery.A binding post 35 is electrically connected to the spring 34, saidspring and post being, however, insulated from the bracket 29 in anysuitable manner. The portion of the bracket apertured to engage thebearing I0 is slit, the slit being bridged by a screw 36, which may beadjusted to allow a rocking of the bracket on the bearing ill, toproperly time the spark, while restraining the bracket from accidentalshifting.

To combine two or more of the described single cylinder engines, thecrank shaft is elongated by adding to it additional throw arms i andshaft sections 9, the latter being squared at both ends to permit suchaddition. The heads H at the mutually adjacent ends of the crank-casesare removed and replaced by a spacer block 31, which exercises the samesealing and bearing function as said heads and further properly spacesthe cylinder blocks to afford a clearance between their fins 2. Thefirst-described bolts 12 are replaced by longer bolts 38, suitable forclamping the engine units firmly together. Thus by combining several ofthe first-described units in a simple manner, there is built up amulti-cylinder engine, increasing the available power as may be desired.

The described engine operates on the usual two cycle principle, drawinga charge into the crank case 4 when the piston is raised, by-passingsuch charge into the combustion chamber when the piston is lowered, andsimultaneously exhausting products of a preceding combustion andcompressing the charge during, and firing it at completion of thefollowing up-strike.

The described sectional form of the crankshaft permits of itsmanufacture by simple and inexpensive operations, and the entire engineis designed throughout to simplify manufacture and assembly and permitof low-cost quantity production. In miniature sizes, productive ofone-half horse power or less, the larger parts may be inexpensivelyformed as die castings, preferably from an aluminum alloy.

The invention is presented as including all such modifications andchanges as come within the scope of the following claims.

What I claim is:

1. In an internal combustion engine, two engine .units each comprising acrank case and a cylinder mounted on the crank case, a crank shaftformed with a crank in each crank case, a spacer interposed between thetwo crank cases and establishing clearance for said cylinders, and meansspanned across the spacer extending exteriorly of the crank cases andoutwardly from the spacer for interconnecting the crank cases andclamping said spacer rigidly between the crank cases.

2. In an internal combustion engine, two engine units each comprising acrank case and cylinder, a crank shaft having a crank in each crankcase, heads closing the relatively remote ends of the crank cases, andmembers extendin exteriorly of the crank case and connecting such forclamping said heads on the crank case.

ORVILLE Z. FRAZIER.

